In 2500,[2] after the rise of the Terran Dominion, Colin's father was touring the mines with his son, having an argument with mine owner Scott Dagget. He was accompanied by a bodyguard of six marines led by Captain Veers, who had lost a son who would have been the same age as Colin. The zerg attacked during the conversation. The group, along with numerous other civilians, took shelter in the mines.[1]

Colin's psionic technique allowed him to know when a horde of invading zerg entered the mine seventy hours after their initial arrival, enabling him to warn the other terrans. His father covered for him, saying he had sharp hearing. Colin bunkered down with his father while Dominion marines engaged in battle with the invaders.

The marines fought off the zerg, but lost one of their number. Piett, one of the marines, tried to reveal that Colin was psychic, and when Captain Veers tried to distract him by reminding him of his brother's fate (being made a part of the Ghost Program), Piett exclaimed that psychics should be used as weapons.

Dagget also believed that Colin was psychic, and the only reason he hadn't been made into a weapon was because of his father's influence. Senator Phash lost his temper and attacked him, but Dagget defeated him.

Piett tried to bring up Colin's unusual abilities; he had a psychic brother and believed him to be a freak. He said that Colin should be made into a weapon just like his brother. Piett tried to convince Veers to use Colin as a trap for the zerg ... along with a quantity of explosives. When Veers disagreed, he shouted out to the gathered civilians that Colin was psychic, and his emanations were drawing the zerg. However, Veers disputed this and said Colin was under his protection.[1]

The group decided to rest for a few hours before Dagget would lead them on a twelve-hour march to a safe bunker. During the night, Piett stealthily approached Colin and mocked him for not seeing this coming. Colin retaliated by scratching Piett's face. Piett kidnapped Colin and tied him to a pillar with some explosives as a trap for the zerg while two of his friends among the marines tried to disable Veers' suit (it didn't work).

Veers freed Colin, but as he did so they were attacked by a pair of zerglings. Colin destroyed one with a psychic attack, but couldn't explain to Veers how he did it; Veers suggested he just didn't know. Unfortunately Veers was struck from behind by the surviving zergling, which mortally wounded him. Veers was able to dispatch the zergling. As he bled to death, he gave final instructions to Colin -- to activate an emergency communication device and then hide from the zerg. He promised he would come back for Colin, but knew this was a lie.

Colin stealthily approached the firefight, and while a zerg saw him, he wasn't attacked. Colin managed to drag his father to the bunker, but this left quite a few bruises, so he apologized to the senator when he woke up. Meanwhile, the rest of the terrans had been killed by the zerg.[1]

The Phashes were rescued by Dominion marines, but as their secret was revealed, the two separated and fled. Colin traveled with Andrew Ballenger, an aide to (now former) Senator Phash. As Corbin sought asylum from the Umojan Protectorate's Minister Jorgensen, Colin and Ballenger moved among refugee camps on various worlds, pursued by the Dominion, especially by wranglerRandall. They couldn't contact Corbin, as this would make them easier to locate. Colin tried to contact his father on at least one occasion, but this turned out to be a Dominion trap, though they were still able to escape.

The pair, posing as father and son, ended up at Gohbus Moon Refugee Camp, a dangerous location as the world Gohbus was about to fall apart due to a terraforming disaster, which would throw the moon out into space. The Dominion couldn't or wouldn't provide enough transport to rescue them, so many of the refugees suffered from nightmares. Colin's growing psychic powers enabled him to pick these up, whether he wanted to or not. He was able to gain some respite by writing letters to his father, albeit ones that he would never be able to send.

Randall tracked them there and offered transport to anyone who revealed Colin's presence, but the refugees refused to cooperate. Randall tried another plan; he would release zerglings which had been "lobotomized" to cut them off from the Zerg Swarm in order to track down Colin. They wore explosive collars to prevent them from turning on the Dominion. Randall believed the refugees would associate the zerg attack with Colin's presence and reveal him, and he was right. However, when Colin sensed the zerg nearby, he used his "quiet voice" power to prevent them from closing in.

Randall intimidated refugees into pointing out Colin's apartment. Colin hid, but Randall was able to ambush and pistol-whip Andrew Ballenger into unconsciousness. Colin spoke to him over Ballenger's comm and showed off his "quiet voice". Randall used his psi-screen against him, causing Colin to scream, revealing his location and breaking his concentration on his ability. The zerglings moved in. Randall moved in, only to be electrocuted by a vengeful Ballenger. The pair tried to fight past zerglings, with Colin using his mental abilities against them, but Ballenger was killed. Colin was "rescued" by reapers and taken to the Ghost Academy. UNN reporter Kate Lockwell "reported" the good news, outraging Corbin. He swore he would expose the Ghost Academy, and Minister Jorgensen offered his support, suggesting he could pass information through Lockwell.[2]

Colin Phash was shown the Ghost Academy by Director Kevin Bick and Superintendent Sarco Angelini. They showed him pro-ghost propaganda before testing him for psionics and endurance. His telepathy was tested by having a group of marines point their rifles at him, and Colin had to pick out which one had loaded their rifle, otherwise he'd be shot. Colin pointed out the right marine.

The Ghost Academy employees found most of Colin's scores high, but his telekinesis and pyrokinesis scores, while higher than those of most ghosts, were inconclusive. Intending to test Colin's quiet voice, Colin was put in an area full of zerg, and Angelini noted that Colin's power effectively shifted his mind to another place. However, when Colin tried to flee the zerg, Angelini broke his power. Colin sent his mind fully out of his body—astral projection.

Interested in this ability, the Ghost Academy hoped to replicate it. Angelini initiated the memory reassignment program on Colin, who saw a vision of his father as it happened.[3]

Colin Phash was subjected to tests by Dr. Gauthier. When Colin was about seven or eight years old, Kevin Bick wanted to assign him to a training team soon, using that increased visibility as a weapon against Corbin Phash's propaganda.[5]

Colin was transferred to a wing generally reserved for older students. While kept hidden, Nova Terra saw him on a few occasions[5] while he was using his astral projection ability. He asked her for help, and once lured her into a restricted area.[6]

The ghostmaster general was dispatched to the Academy in order to pick Colin Phash up and evaluate his astral projection ability. Kevin Bick and Sarco Angelini opposed this agenda, preferring to hold onto the young psychic. A frightened Phash hid from his handlers, prompting Angelini to seek him out. Angelini tried to befriend him.

Phash was ordered to demonstrate his projection ability by finding three hidden Arcturus Mengsk holograms while being viewed by the ghostmaster. However, he lied about their locations, prompting the ghostmaster to denounce Bick as a fraud and storm out. Phash later admitted to Angelini that he had deliberately failed the test because he would rather stay at the Academy than go with the ghostmaster.[7]

Colin is considered very good at hiding. His powers make him good at sensing the zerg.[1]

He has high endurance and strong telepathic powers. His telekinetic and pyrokinetic ratings are higher than that of most ghost trainees, but that testing was inconclusive.[3] His PI is rated at 7.5.[5] Colin has demonstrated a psychic attack ability powerful enough to destroy zerglings.[2]

Colin also has a "quiet voice" ability, which he can use to evade notice from the zerg. It works by shifting his mind to another plane, and he can even send his mind entirely out of his body—this is called astral projection. The Ghost Program considers this extremely interesting, and wishes to replicate it.[3]

The creators of Colin Phash, Frontline writers Paul Benjamin and Dave Shramek, designed him as a character essentially caught up in survival horror, beginning with the zerg and later dealing with his rampant psionic powers. Over the course of the series, his persona was designed to steadily mature, going through a phase in each installment of the series. In a sense, he is a symbol of the darker side of the Ghost Academy and the Dominion's treatment of psychic children.[8]

Colin's powers were toned down in the first draft of Weapon of War, as he was expected to be a oneshot character. This later changed.[9]